/* =========================================================
   複製自 https://cc.mgt.ncu.edu.tw/css/base.css
   （已移除站內未使用的搜尋介面樣式；其餘保持一致，
     主站更新配色時可直接以主站檔案覆蓋）
   ========================================================= */

/* =========================================================
   設計 tokens：光色為預設，暗色以 prefers-color-scheme 覆寫
   所有文字/背景組合皆經驗證達 WCAG AA (≥4.5:1)
   ========================================================= */
:root {
  color-scheme: light dark;
  --bg: #ffffff;
  --surface: #f3f6f9;
  --text: #2e353b;
  --muted: #5c6770;
  --border: #d7dde3;
  --brand: #003366;
  --brand-strong: #00224d;
  --link: #003366;
  --link-hover: #00224d;
  --nav-bg: #003366;
  --nav-text: #ffffff;
  --footer-bg: #003366;
  --footer-text: #ffffff;
  --footer-dim: #c5d3e3;
  --focus: #0056b3;
  --nav-focus: #ffffff;
  --code-bg: #f4f5f7;
  --font-sans: "Noto Sans TC", "PingFang TC", "Microsoft JhengHei", "Heiti TC", system-ui, -apple-system, "Segoe UI", Arial, sans-serif;
  --font-mono: ui-monospace, "Cascadia Mono", Consolas, Menlo, monospace;
}

/* 手動切換為暗色（data-theme="dark"）。
   注意：此區塊與下方 media query 內的 tokens 需保持同步 */
:root[data-theme="dark"] {
    --bg: #14181d;
    --surface: #1d242c;
    --text: #d9dee3;
    --muted: #a6b0ba;
    --border: #39424c;
    --brand: #8fb9e8;
    --brand-strong: #b3d1f2;
    --link: #8fb9e8;
    --link-hover: #b3d1f2;
    --nav-bg: #0f2036;
    --nav-text: #ffffff;
    --footer-bg: #0f2036;
    --footer-text: #e6ebf1;
    --footer-dim: #a6b0ba;
    --focus: #8fb9e8;
    --code-bg: #1d242c;
}

/* 未手動選擇時跟隨系統偏好 */
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #14181d;
    --surface: #1d242c;
    --text: #d9dee3;
    --muted: #a6b0ba;
    --border: #39424c;
    --brand: #8fb9e8;
    --brand-strong: #b3d1f2;
    --link: #8fb9e8;
    --link-hover: #b3d1f2;
    --nav-bg: #0f2036;
    --nav-text: #ffffff;
    --footer-bg: #0f2036;
    --footer-text: #e6ebf1;
    --footer-dim: #a6b0ba;
    --focus: #8fb9e8;
    --code-bg: #1d242c;
  }
}

/* 手動選擇時鎖定 color-scheme（影響表單控件與捲軸） */
:root[data-theme="light"] {
  color-scheme: light;
}

:root[data-theme="dark"] {
  color-scheme: dark;
}

/* ===== 基本重設與全站字體 ===== */
* {
  padding: 0;
}

html {
  font-size: 100%;
}

body {
  margin: 0;
  background-color: var(--bg);
  color: var(--text);
  font-family: var(--font-sans);
  font-size: 1rem;
  line-height: 1.8;
  text-rendering: optimizelegibility;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body.hidden {
  overflow: hidden;
  padding-right: 6px;
}

#app {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

/* ===== 捲軸 ===== */
::-webkit-scrollbar {
  background-color: transparent;
  width: 8px;
  height: 8px;
  background-clip: padding-box;
}

::-webkit-scrollbar-thumb {
  background-color: rgba(144, 147, 153, .5);
  border-radius: 5px;
}

::-webkit-scrollbar-thumb:hover {
  background-color: #a4a4a4;
}

/* ===== 連結 ===== */
a {
  color: var(--link);
  text-decoration: none;
  background-color: transparent;
  transition: color 0.2s ease, background-color 0.2s ease;
}

a:hover {
  color: var(--link-hover);
  text-decoration: underline;
}

img {
  border: none;
  max-width: 100%;
}

/* ===== 標題 ===== */
h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-sans);
  color: var(--text);
  line-height: 1.4;
}

h1 {
  font-size: 1.625rem;
  font-weight: 700;
  color: var(--brand);
  text-align: center;
  letter-spacing: .06em;
  margin: .5rem 0 1.75rem;
}

h2 {
  font-size: 1.25rem;
}

/* ===== 內容區（.markdown-body：公告與各頁面共用） ===== */
.markdown-body {
  line-height: 1.9;
}

.markdown-body h2 {
  color: var(--brand);
  text-align: left;
  border-left: 4px solid var(--brand);
  padding-left: .75rem;
  margin: 2.2rem 0 1rem;
}

.markdown-body a {
  color: var(--link);
  text-decoration: underline;
  text-underline-offset: 3px;
}

.markdown-body a:hover {
  color: var(--link-hover);
}

.markdown-body ul,
.markdown-body ol {
  padding-left: 1.6em;
  margin: 1em 0 1.5em;
}

.markdown-body li {
  margin: .3em 0;
}

.markdown-body p {
  margin: 1em 0 1.4em;
}

/* ===== 日期樣式（公告頁） ===== */
.post-date, .date {
  font-size: .875rem;
  color: var(--muted);
  display: block;
  font-variant-numeric: tabular-nums;
}

/* ===== 回到頁首 ===== */
.back-to-top {
  position: fixed;
  right: 1.25rem;
  bottom: 1.5rem;
}

.back-to-top.hidden {
  display: none;
}

.back-to-top button {
  width: 44px;
  height: 44px;
  border: 0;
  border-radius: 50%;
  background: var(--nav-bg);
  color: var(--nav-text);
  cursor: pointer;
  font-size: 1.1rem;
  box-shadow: 0 2px 8px rgba(0, 0, 0, .25);
  display: inline-flex;          /* 本頁改用 inline SVG 圖示，置中用 */
  align-items: center;
  justify-content: center;
}

.back-to-top button:hover {
  background: var(--brand-strong);
}

:root[data-theme="dark"] .back-to-top button:hover {
  background: #1a3a5c;
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) .back-to-top button:hover {
    background: #1a3a5c;
  }
}

/* ===== 跳至主要內容連結（預設隱藏，Focus 時顯示） ===== */
.skip-link {
    position: absolute;
    top: -100px;
    left: 0;
    background-color: #000;
    color: #fff !important;
    padding: 10px 20px;
    z-index: 99999;
    text-decoration: none;
    font-size: 1rem;
    transition: top 0.3s ease;
    border-radius: 0 0 5px 0;
}

.skip-link:focus {
    top: 0;
    outline: 3px solid #7eb3ff;
}

/* ===== 全站鍵盤焦點樣式（符合 CS1140101E 規範） ===== */
a:focus, summary:focus, button:focus {
    outline: 2px dashed var(--focus);
    outline-offset: 2px;
    text-decoration: none;
}

a:focus img {
    outline: 2px solid #d9534f;
    box-shadow: 0 0 8px rgba(0,0,0,0.5);
}

/* skip link 跳入 main 時不需顯示外框（程式焦點，非鍵盤循序焦點） */
main:focus {
    outline: none;
}

/* ===== 螢幕報讀器專用文字 ===== */
.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}